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Industrial Maintenance and Reliability
Conference:
Making Bearings Reliable
Per Arnold Elgqvist
Director,
TRIBOLOGIA APLICADA, S.A. DE C.V.
Industrial Maintenance and Reliability
Bearing Reliability
¡It’s very easy to achieve Reliable
Rolling Element Bearings!
(Specially when you know how!)
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Industrial Maintenance and Reliability
Knowing and applying the
Best Practices
as working methods
most bearing premature failures can be
avoided in the industry.
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Industrial Maintenance and Reliability
The Best Practices to achieve bearing
reliability are very simple and logical and
several of them do not even require extra
costs or additional investments.
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Industrial Maintenance and Reliability
¿Which are these
Best Practices
for Bearing Maintenance?
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Industrial Maintenance and Reliability
Some of the very Best Practices for Bearing Maintenance are:
• The Right Bearing for each and every Application.
• Keep the Bearings clean (Virgins) until their Mounting.
• Avoid Handling Damages (Impacts on the Balls hurt).
• The Correct Fits and Quality on Shafts and in Housings.
• Avoid Mounting damages.
• The Correct Lubrication for each and every Application.
• Avoid unnecessary Preventive Maintenance through
Predictive and Proactive Maintenance.
Don’t Generalize!!!!!
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Industrial Maintenance and Reliability
¿How can we avoid
this type of
failures?
¡This bearing
241/900 with a
weight of 3.3 tons
lasted for 105
hours in operation!
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Industrial Maintenance and Reliability
How many failures are caused by incorrect lubrication?
Ref. FAG
++
= 55%
20
20% Incorrect lubricant
15% Lack of lubricant
20% Degraded lubricant
< 1% Material or manufacturing defects
10 % Incorrect bearing (load capacity, seals, internal clearance)
20 % Solid particle contamination
5 % Liquid contamination
5 % Handling and mounting damages
5 % Other causes
Industrial Maintenance and Reliability
A correct lubrication must include …………
• The selection of the correct lubricant.
• Applied with the correct system.
• Applied at the correct point.
• Applied with the correct quantity.
• Applied at the correct time.
• Applied by the correct person,
knowledgeable and well trained.
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Industrial Maintenance and Reliability
¿How can we assure the use of the right lubricant?
1. Selecting the optimal lubricant for each and every
application.
2. Specifying at least 5 properties, both for greases
and oils.
¡Don’t generalize!
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Industrial Maintenance and Reliability
The persons responsible for the
lubrication must be true TRIBOLOGISTS
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Industrial Maintenance and Reliability
The particle contamination shorten bearing life according to the ISO 281/2 much more than we thought.
Ref. FAG
+= 25%
20% Incorrect lubricant
15% Lack of lubricant
20% Degraded lubricant
< 1% Material or manufacturing defects
10 % Incorrect bearing (load capacity, seals, internal clearance)
20 % Solid particle contamination
5 % Liquid contamination
5 % Handling and mounting damages
5 % Other causes
Industrial Maintenance and Reliability
Application CENTRIFUGAL PUMP
Bearings: 7208 BECBM in Back-to-Back arrangement
Loads: Axial Fa: 7,000 N Radial Fr: 500 N
Speed: 1800 rpm
Operating
TemperatureContamination Level (Calc. Factor) Actual Viscosity v
Viscosity
Relation v/v1Factor aSKF Bearing Life L10nm
ºC ηc cSt κ Hours
OIL BATH LUBRICATION Mineral Oil ISO VG 68
OIL MIST LUBRICATION Mineral Oil ISO VG 68
1 70 Normal ISO 18/15/12 0.5 20.2 1.5 6.3 32,000
2 70 Moderate Contamination ISO 20/17/14 0.2 20.2 1.5 1.7 8,970
3 70 Heavy Contamination ISO 22/19/16 0.1 20.2 1.5 0.9 4,610
1 60 Normal ISO 18/15/12 0.5 28.7 2.1 8.8 45,400
1 60 Improved Cleanliness ISO 16/13/10 0.8 28.7 2.1 24.7 127,000
Bearing life calculation according to ISO 281/2:2000 utilizing SKF method
The Benefits: Oil Mist vs. Oil Bath in Centrifugal Pumps
Ref: Conference by Per Arnold Elgqvist, May 2005, STLE 2005 Annual Meeting, Las Vegas, USA
Industrial Maintenance and Reliability
“Bearings should be kept as Virgins until
their mounting”
My recommendation:
Industrial Maintenance and Reliability
¡Wrong Bearing is the 2nd biggest cause
for bearing premature failures!
¿Why do I say this?
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Industrial Maintenance and Reliability
The lack of knowledge of bearing designations is
the main reason for the usage of wrong bearings:
Examples (Suffixes):
What do the suffix C3 indicate?
Are bearings with the suffix 2Z or ZZ really
sealed?
For which bearing types is it indispensable to
specify the type of cage?
What indicates CB in SKF or UA in FAG?
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Industrial Maintenance and Reliability
¡Wrong Bearing is the 2nd biggest cause
for bearing premature failures!
Example (Suffixes):
Which is the importance
of the suffixes CB for SKF
and UA for FAG bearings
of the type 7 (Single row
angular contact ball
bearings)?
Industrial Maintenance and Reliability
Simple example of wrong Bearing:
Monophasic electrical motor: Bearing 6203-2Z works
perfect.
Automotive alternator: Bearing 6203-2Z won’t work!
1760 RPM vs. 16,000 to 20,000 RPM
Mostly clean environment vs. dusty and hot environment
(+ motor washings)!
Bearings for alternators therefor need:
Greater internal clearance than Normal +
High temperature grease +
Contact seals.
Industrial Maintenance and Reliability
Look at the real problem: The enormous world of suffixes.
Examples (SKF):
6205-2RS1NRTN9/P63LT20CVB123
23064 CCK/HA3C084S2W33
6205-2RS1 NR TN9 / P63 LT20C VB123
23064 CC K / HA3 C084 S2 W33
Industrial Maintenance and Reliability
Opportunities for the
CMMS Systems
Material Texto Complementario Ref. SKF
100010463 SKF 7310
7310 BECBM
100010505 SKF 7310BG / ROLLWAY 7310BCB / 7310 BECB
100010505 SKF 7310BG / ROLLWAY 7310BCB / 7310 BECB
100010505 SKF 7310BG / ROLLWAY 7310BCB / 7310 BECB
100010505 SKF 7310BG / ROLLWAY 7310BCB / 7310 BECB
100010505 SKF 7310BG / ROLLWAY 7310BCB / 7310 BECB
100010505 SKF 7310BG / ROLLWAY 7310BCB / 7310 BECB
100010505 SKF 7310BG / ROLLWAY 7310BCB / 7310 BECB
100010562 SKF 7310 B
100010562 SKF 7310 B
100010562 SKF 7310 B
100010562 SKF 7310 B
100010562 SKF 7310 B
100010562 SKF 7310 B
100010562 SKF 7310 B
100010586 FAG 7310BUO
100024093 SKF 7310BG / ROLLWAY 7310BCB / 7310 BECB
100026265 SKF 7310
100026265 SKF 7310
100026265 SKF 7310
100026265 SKF 7310
100026265 SKF 7310
100026265 SKF 7310
100026265 SKF 7310
100026265 SKF 7310
100030353 SKF 7310BG / ROLLWAY 7310BCB / 7310 BECB
100038446 FAG 7310BJP
100055771 X TODA MARCA 7310BECBY
100055771 X TODA MARCA 7310BECBY
100055771 X TODA MARCA 7310BECBY
100055789 SKF 7310
100080937 SKF 7310BEAG
100080937 SKF 7310BEAG
100125459 BYRON JACKSON PARTE NO. 7310
12 different SAP Numbers, but
Not one single is correct!
Industrial Maintenance and Reliability
How many of You can assure me that
the Bearings in your warehouses are:
1. The Correct and
2. Are in Perfect Conditions (Virgins)
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Industrial Maintenance and Reliability
How shall a Warehouse be administrated?
As a Supermarket:
Package you open =
Product you must take out from the Warehouse
Industrial Maintenance and Reliability
Does this
inspire
Reliability?
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Industrial Maintenance and Reliability
And these?
Industrial Maintenance and Reliability
“Bearings are innocent until you can prove the opposite”
“Bearings have First Name and Second Name”
“Bearings must reach their Mounting still being Virgins”
“The Warehouse must be administrated as a Supermarket”
“The conditions of the Bearings in the Warehouse indicate
the Bearing Culture in the Plant“
“The Reliability starts with the Bearings in the Warehouse”
Some Key Messages:
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Industrial Maintenance and Reliability
Effects of out of roundness of bearing seating on bearings:
Example: Electrical motor:
Housing roundnessRoundness of the
raceway before mounting
( Talyrond, resolution 2μm)
Roundness of the
raceway after mounting
Bearing Fits on Shaft and in Housing:
Bearings are Innocent until
you can prove the opposite!
Industrial Maintenance and Reliability
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Bearing Mounting:
Mounting forces must always be
applied to the ring you are mounting!
Industrial Maintenance and Reliability
“Impacts on the Balls hurt”
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Industrial Maintenance and Reliability
The Challenge for Maintenance:
Advise: Implement Predictive, or even
better, a Proactive Maintenance
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“To do the correct job, at the correct
moment and to do it correctly”
Result: Increased Efficiency
Industrial Maintenance and Reliability
Recommended service life from the manufacturer for the
pre-established operating conditions
“Infant
mortality”
Run-in period
Requirement of intensive
TEMPORARY condition monitoring
Start-up of the machine:
• Tests after the installation
• Intensive condition monitoring
until stability is reached
Wear period
• Condition monitoring at the
end of the life cycle
Unnecessary Preventive Maintenance:
Unnecessary spending, new run in period, new risks
of totally unnecessary failures!
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How is the life cycle of an equipment?
Vibrations.
Noise,
temperature
Industrial Maintenance and Reliability
1. Detection(Condition
Monitoring)
2. Analysis(Vibration Analysis, Oil Analysis,
Root Cause Failure Analysis)
3. Correction(Key Performing Indicators)
¡Close the Circle!
4. Follow UPReview the results of the
corrective actions
Don’t forget to close the circle!
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Industrial Maintenance and Reliability
Lubrication
Wrong Bearing
Contamination
Misalignment
Wrong Setup
OverloadFitting Practices
False Brinelling
Low Quality Seating
Electrical Etching
Handling Damages
Operational Errors
Opportunity: My workshop Bearing Failure Analysis, tomorrow 10:45 to 11:45
Industrial Maintenance and Reliability
¡Thanks for your Attention and
Good Luck!
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